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Basic LFM Operation

This section outlines the basic operational procedures involved in obtaining data in Lateral Force Mode. Before attempting to take LFM images, you should be familiar with taking Contact AFM mode images with the MultiMode 8. Ensure that the system is installed and set up correctly.

Probe Requirements

LFM is typically performed with low spring constant silicon nitride "A" shaped cantilevers.

After performing Contact Mode imaging, LFM images may be taken without interrupting the imaging session.

HINT: The Contact Mode setpoint voltage will affect the magnitude of the lateral force signal. If the frictional effects are too large or too small, change the cantilever. But if the value is near the dynamic range desired, adjustment of the Contact Mode setpoint voltage will produce modest changes in the lateral force or frictional signal. By increasing the setpoint, the contact force applied will increase, and so will the frictional or torsional forces in an approximately linear fashion.

Steps to acquiring LFM data:

1. Set Up the Experiment
2. Load a sample.
3. Load a probe and insert the probe holder.
4. Align the laser and photodetector.
5. Using the Check Parameters view, review the preloaded scan parameters and modify them as needed.
6. Engage on the sample and scan.
NOTE: LFM is a qualitative measurement, not quantitative. NanoScope software does not provide a way to calibrate the torsional spring constant of a cantilever.
NOTE: The trace and retrace LFM signals may not be the same magnitude. The tip will never be exactly perpendicular to the sample. In most cases, internal stress in the material of the cantilever will cause the cantilever to have a natural bias in some direction.

 

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